1. Field of the Invention
The present invention relates to a timepiece, such as watch, which has a bezel rotation-operated.
2. Description of the Related Art
There is known a timepiece in which there is made such that the bezel arbitrarily rotation-operated by a user does not move carelessly from its rotated position (e.g., refer to JP-A-11-118951 Gazette (Paragraphs 0025-0051, FIG. 1-FIG.  5)).
In the timepiece of the JP-A-11-118951 Gazette (Paragraphs 0025-0051, FIG. 1-FIG. 5), the bezel is disposed so as to be rotatable while surrounding a cover glass installed in a case band, a regulation protrusion provided in an inner periphery of this bezel is engaged from a lower side with a regulation protrusion provided in an outer periphery of a site surrounding the cover glass of the case band, the bezel is held to the case band so as not to be removed in an upward direction, and a threaded part is formed in a lower part outer periphery of the site surrounding the cover glass. And, between the case band and the bezel, a threaded ring engaging with a threaded part is disposed so as to be capable of being rotation-operated.
According to this timepiece of the JP-A-11-118951 Gazette (Paragraphs 0025-0051, FIG. 1-FIG. 5), by the fact that the threaded ring is separated from a lower face of the bezel by rotation-operating the threaded ring, a rotation operation of the bezel is permitted. Reversely to this, by the fact that the bezel is pushed up by rotation-operating the threaded ring in a reverse direction to thereby be pushed to the lower face of the bezel, it is possible to fix the bezel to the case band by mutually butting the above regulation protrusions.
In the prior art, by a frictional force between the threaded ring and the bezel lower face and a frictional force between the both regulation protrusions of the case band and the bezel, since the bezel is fixed so as not to rotate, it is unavoidable that, just before this fixation completes, a rotation operation force of the threaded ring is exerted on the bezel and this becomes gradually large. By this, such a fear is high that the bezel is rotated in conjunction with the threaded ring which is rotation-operated, and deviates from a desired position.
Additionally, in the prior art, since the threaded ring is rotation-operated, not only it is inconvenient in the operation, and, since the user judges the fact that the bezel became a fixed state by the fact that the rotation operation of the treaded ring became heavy, this judgment is liable to disperse. By this, there is a possibility that an excess or deficiency occurs in the fixation of the bezel, and also a possibility that the threaded ring loosens is high.
Moreover, in the prior art, a pushing-up force, of the threaded ring, for fixing the bezel is received by the both regulation protrusions of the case band and the bezel. Since these regulation protrusions are small and their strengths are low, such a probability is high that, by a force exerted as the bezel is repeatedly fixed, the both regulation protrusions deform and a reliability suitably fixing the bezel lowers.